It is known to place a cell suspension in a generally tubular sample chamber having an open end juxtaposed to the surface of a microscope or like slide, with the interposition of an apertured filter card that both provides a seal between the sample chamber and the slide surface and also serves to absorb the liquid components of the suspension. The assembly of sample chamber, slide and filter card is subjected to centrifugation to cause the deposition of a layer of cells on the slide surface and the removal of the suspension liquid into the filter card. One example of cytocentrifugation apparatus especially adapted to perform this cell separation and deposition technique is disclosed in U.S. Pat. No. 4,391,710. U.S. Pat. No. 4,576,110 discloses a similar technique which, however, replaces the filter card with an absorbent plug communicating with a deposition area on the slide.
Prior to microscopic or like examination, the deposited cell layer on the slide requires at least fixation and may also require staining or other procedures to be applied thereto. Hitherto, any such after-treatment of the deposited cell layer has been accomplished after the centrifugation operation has been concluded and the assembly of sample chamber and slide has been dismantled to permit the slide and the cell layer deposited thereon to be recovered for such further processing and subsequent examination, the further processing--e.g. fixation--being effected by conventional manual or automated techniques for such purposes.
The freshly deposited cell layer on the slide is vulnerable to damage and degradation by handling and delay between its deposition and the subsequent processing treatment to which it is subjected. In a busy laboratory handling many such cell deposits by automated or semi-automated techniques, the making up of batches of slides bearing freshly deposited cell layers for such processing carries with it a substantial risk of damage and degradation of individual cell deposits.
A more specific objective of the present invention is therefore to provide for accomplishing at least one protective treatment of a freshly deposited cell layer as an adjunct to the centrifugation procedure and prior to any dismantling of the assembly of sample chamber and slide and, indeed, with the minimum disturbance of the assembly.